In the processing of work pieces when automatically feeding the raw parts, it is necessary that the work pieces arriving successively on a conveying means are grasped and that they are passed after they have been centered to a gripper of a loading arrangement or directly to the tension chuck of a machine tool. For this purpose, a so-called transfer box has been arranged at the end of a conveyer belt or a chain conveyer, into which the individual work pieces are transported and from which the work pieces can be taken over by a gripper of a loading arrangement. The box is frequently constructed as a hinged box in order to bring the work pieces, which arrive lying flat, into an upright position. In this arrangement, the box has fixedly adjusted stops, which are set for the particular work piece diameter in order to center the arriving work piece, which is pressed by the conveying means against the stops for the centered transfer to the gripper. Of disadvantage in such transfer boxes is the fact that they are prepared only for work pieces of a given diameter, and that--when moving to other work pieces--the box must be changed. This is not only time-consuming but also extremely tedious because this transfer box is located behind the processing room and the operator must carry out the exchange either from above through a corresponding entry hatch or through the work space of the machine tool. Not only must safety precautions be maintained in order to avoid danger of injury within the working space, but this process is also tedious because of the position of the transfer box, which is difficult to access, and the fact that the working space is contaminated with coolants and chips.
A further disadvantage of this transfer box is that the work piece rests only against stops and is not clamped, so that, when transferring it to a gripper chuck, it must be assured that the work piece does not move from its stops before the gripper chuck has gripped it securely.